1. Field of the Invention
The present invention relates generally to rack mounted server or computer systems. More particularly, the preferred embodiments of the present invention relate to power control in rack mounted server systems where the power supplies are centralized. More particularly still, the preferred embodiments of the present invention relate to allocation and de-allocation of power in a rack mounted server system having a central power supply system.
2. Background of the Invention
In rack mounted server systems constructed before this invention, each server mounted horizontally in the rack. Thus, observing the front of a previous rack mounted server system, there are a plurality of servers extending from near the bottom of the rack to near the top of the rack, each mounted horizontally.
Each computer or server of previous rack mounted server systems is a stand-alone computer that includes one or more processors, RAM, fixed disks, AC to DC power supplies, and the like. In fact, these servers may have as many as three power supplies within each server such that redundancy is accomplished by having the server operational on only two of those three power supplies. AC to DC power supplies however occupy significant space.
The standard unit of measure for indicating the density of rack mounted server systems is a unit “U” equal to 1.75 inches. Thus, if a computer or server has a 4U density, that server has a thickness of 7 inches. As of the writing of this specification, commercial rack mounted server systems have servers therein with a 1U thickness, where those servers are mounted horizontally in the rack.
In order to decrease server footprint, and thus increase the number of servers that may be placed within a rack, it has been proposed to remove the individual AC to DC power supplies from the servers and place those power supplies at a central location, e.g., near the bottom of the rack. By removing the power supplies from the individual servers within the rack, it is possible to decrease the size of the servers to less than 1U. While removing power supplies and centralizing those supplies within the rack mounted server system may aid in decreasing the footprint of each individual server, this separation of the power supplies from the servers creates problems with regard to how to manage the shared power supply resource, as well as how to allocate and deallocate power during normal and emergency operating conditions.
Thus, what is needed in the art is a way to intelligently control allocation and de-allocation of power in a rack mounted server system with a central power supply system.